In the Windows project generator: Handle swig as a dependency library.
* build.conf (libsvn_swig_py, libsvn_swig_perl, libsvn_swig_ruby): Use swig. (swig): New external library.
* build/generator/gen_win.py (__init__, get_install_targets): Check for swig as library. (get_win_includes): Simplify logic.
* build/generator/gen_win_dependencies.py (find_libraries): Only check for perl, python, ruby if swig is found. (_find_ruby): Find more include paths in an attempt to really get it working. (_find_swig): Modernize detection. Pass our own swig paths for includes.
Replace specialized handling of the jdk paths in the windows project generator with using the standard dependency framework.
* build.conf (libsvnjavahl): Mark dependency on the jdk. (java-sdk): New external library project. Currently not really a library.
* build/generator/gen_win.py (get_install_targets): Check for library existance. (get_win_includes): Remove unused common include dir and jdk includes. (get_win_lib_dirs): Easy out on libraries that don't link dependencies directly. (get_win_libs): Remove unused code.
* build/generator/gen_win_dependencies.py (get_win_lib_dirs): Add optional library. (find_libraries): Always locate the jdk. (_find_jdk): Create a library instance with build information.